Rocking Chair: Part 2

Monday after work I started on attaching the rockers.  These are attached using a pinned bridle joint.  I drew a line that passed through the center of the front and rear posts using a yardstick, then using dividers set to half the thickness of the rocker marked one side.  I then positioned the rocker on the posts and scribed the other side using an old planer blade since I couldn't get my marking knife flush with the rocker.  After that I drew some lines along the post to help my sight vertical and cut each side.

Then using my 1/2" mortise chisel bashed out the waste.  Then I used a rasp and a float to finesse the fit.  The rasp was great at taking off a lot of wood, and is nice and wide providing a nice flat surface, however due to the diligence of the Frenchman that peened it, it does not have a safe edge.  To get into the bottom of the mortise without messing up my square baseline I used my Iwasaki "rasps" which I use as a float, which does have a safe edge.  After the sides of the bridle matched the rocker, it was time to see how it rocked.  I was surprised at how much it reclined in use, and by moving the rockers forward and backward I was able to find the "sweet" spot, that make it feel a little more stable.  Due to the shape of the rockers the mortise in the front posts need to be undercut pretty significantly, and the floor of the rear posts need to be slanted.  I used my paring chisel for that.  Once the rocker sat flush in the joints I drilled a 5/16" hole, and glued and pinned the joints.  It's important to think about where to apply clamping pressure.  In the case of a bridle joint, you want to clamp it so that the tenon gets squeeze between the to walls as shown below.

Tuesday I started cutting the joinery for the arms.  The arms are attached with a 3/4" round tenon at the front post, and a 1/2" round tenon into the rear post.  I transferred the distance between the center of the front post and back post and marked that as the shoulder for the arm.  I cut the arms 1/2" longer than the shoulder to allow for the tenon.  I cleaned that up with a block plane then used a compass to draw a 1/2" circle (in my case slightly larger).  I cut down to the shoulder using my dovetail saw. Then cleaned and fitted it with a rasp.

Scored shoulder and slightly oversized tenon pattern.

Cut to the lines.

Remove the waste.

I drew a small circle inside to help keep things round.

As I got closer I used a setup block to test the tenon.

Nice tight fit.

Testing the fit at the shoulder too.

After I was satisfied with the test fit I bored the hole in the rear post and tested the fit in place.

The shoulder gets a slight curve to match the post

Finally I drill through the back to accommodate a screw (this will get a plug later), and clamp the arm to the rail to keep the front joint flush.

Arm in place

All that's left is to make sure I didn't miss any glue before applying the finish

Watching glue dry